A new Eurosceptical party is on the brink of entering the German Parliament for the first time, an opinion poll showed, casting doubt on Chancellor Angela Merkel’s bid to maintain her centre-right coalition and complicating her eurozone policy.

Merkel still looks set to secure a third term in Sunday’s general election. But the Alternative for Germany (AfD), which has risen on a tide of public hostility to bailouts of indebted southern eurozone countries, could further fragment the lower house, forcing her into a right-left “grand coalition”.

A breakthrough for the party, which advocates forcing weaker members out of the single currency area, would send shock waves around Europe and could spook financial markets, even though its voice in Parliament would be small.

An Insa poll yesterday gave Merkel’s conservatives 38 per cent and their liberal Free Democrat (FDP) allies six per cent, putting the centre-right one point behind the three left-of-centre opposition parties, with a combined 45 per cent. The survey was the first to show the AfD, created just seven months ago, clearing the five per cent hurdle to win seats in the Bundestag lower house. Its best score in other polls has been four per cent, but pollsters say it may have higher unavowed support.

If the AfD becomes the first new party to enter the Bundestag since 1990, Merkel would probably have to negotiate a coalition with the pro-European opposition Social Democrats (SPD), with whom she governed in 2005-2009.

The Insa poll was also the first to be taken after Bavarian conservatives won a regional election last Sunday – but it showed no bounce for Merkel in the national race.